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Part of the female reproductive tract From Wikipedia, the free encyclopedia
In mammals and other animals, the vagina (pl.: vaginas or vaginae)[1] is the elastic, muscular reproductive organ of the female genital tract. In humans, it extends from the vulval vestibule to the cervix (neck of the uterus). The vaginal introitus is normally partly covered by a thin layer of mucosal tissue called the hymen. The vagina allows for copulation and birth. It also channels menstrual flow, which occurs in humans and closely related primates as part of the menstrual cycle.
 | It has been suggested that this article be split into a new article titled Human Vagina. (discuss) (November 2024) |
| Vagina | |
|---|---|
Normal adult human vagina, before (left) and after (right) menopause | |
 Diagram of the female human reproductive tract and ovaries | |
| Details | |
| Precursor | Urogenital sinus and paramesonephric ducts |
| Artery | Superior part to uterine artery, middle and inferior parts to vaginal artery |
| Vein | Uterovaginal venous plexus, vaginal vein |
| Nerve |
|
| Lymph | Upper part to internal iliac lymph nodes, lower part to superficial inguinal lymph nodes |
| Identifiers | |
| Latin | vagina |
| MeSH | D014621 |
| TA98 | A09.1.04.001 |
| TA2 | 3523 |
| FMA | 19949 |
| Anatomical terminology | |
To accommodate smoother penetration of the vagina during sexual intercourse or other sexual activity, vaginal moisture increases during sexual arousal in human females and other female mammals. This increase in moisture provides vaginal lubrication, which reduces friction. The texture of the vaginal walls creates friction for the penis during sexual intercourse and stimulates it toward ejaculation, enabling fertilization. Along with pleasure and bonding, women's sexual behavior with other people can result in sexually transmitted infections (STIs), the risk of which can be reduced by recommended safe sex practices. Other health issues may also affect the human vagina.
The vagina has evoked strong reactions in societies throughout history, including negative perceptions and language, cultural taboos, and their use as symbols for female sexuality, spirituality, or regeneration of life. In common speech, the word "vagina" is often used incorrectly to refer to the vulva or to the female genitals in general.
The term vagina is from Latin vāgīna, meaning "sheath" or "scabbard".[1] The vagina may also be referred to as the birth canal in the context of pregnancy and childbirth.[2][3] Although by its dictionary and anatomical definitions, the term vagina refers exclusively to the specific internal structure, it is colloquially used to refer to the vulva or to both the vagina and vulva.[4][5]
Using the term vagina to mean "vulva" can pose medical or legal confusion; for example, a person's interpretation of its location might not match another's interpretation of the location.[4][6] Medically, one description of the vagina is that it is the canal between the hymen (or remnants of the hymen) and the cervix, while a legal description is that it begins at the vulva (between the labia).[4] It may be that the incorrect use of the term vagina is due to not as much thought going into the anatomy of the female genitals as has gone into the study of male genitals, and that this has contributed to an absence of correct vocabulary for the external female genitalia among both the general public and health professionals. Because a better understanding of female genitalia can help combat sexual and psychological harm with regard to female development, researchers endorse correct terminology for the vulva.[6][7][8]
The human vagina is an elastic, muscular canal that extends from the vulva to the cervix.[9][10] The opening of the vagina lies in the urogenital triangle. The urogenital triangle is the front triangle of the perineum and also consists of the urethral opening and associated parts of the external genitalia.[11] The vaginal canal travels upwards and backwards, between the urethra at the front, and the rectum at the back. Near the upper vagina, the cervix protrudes into the vagina on its front surface at approximately a 90 degree angle.[12] The vaginal and urethral openings are protected by the labia.[13]
When not sexually aroused, the vagina is a collapsed tube, with the front and back walls placed together. The lateral walls, especially their middle area, are relatively more rigid. Because of this, the collapsed vagina has an H-shaped cross section.[10][14] Behind, the upper vagina is separated from the rectum by the recto-uterine pouch, the middle vagina by loose connective tissue, and the lower vagina by the perineal body.[15] Where the vaginal lumen surrounds the cervix of the uterus, it is divided into four continuous regions (vaginal fornices); these are the anterior, posterior, right lateral, and left lateral fornices.[9][10] The posterior fornix is deeper than the anterior fornix.[10]
Supporting the vagina are its upper, middle, and lower third muscles and ligaments. The upper third are the levator ani muscles, and the transcervical, pubocervical, and sacrocervical ligaments.[9][16] It is supported by the upper portions of the cardinal ligaments and the parametrium.[17] The middle third of the vagina involves the urogenital diaphragm.[9] It is supported by the levator ani muscles and the lower portion of the cardinal ligaments.[17] The lower third is supported by the perineal body,[9][18] or the urogenital and pelvic diaphragms.[19] The lower third may also be described as being supported by the perineal body and the pubovaginal part of the levator ani muscle.[16]
The vaginal opening (also known as the vaginal introitus and the Latin ostium vaginae)[20][21] is at the posterior end of the vulval vestibule, behind the urethral opening. The term introitus is more technically correct than "opening", since the vagina is usually collapsed, with the opening closed. The opening to the vagina is normally obscured by the labia minora (inner lips), but may be exposed after vaginal delivery.[10]
The hymen is a thin layer of mucosal tissue that surrounds or partially covers the vaginal opening.[10] The effects of intercourse and childbirth on the hymen vary. Where it is broken, it may completely disappear or remnants known as carunculae myrtiformes may persist. Otherwise, being very elastic, it may return to its normal position.[22] Additionally, the hymen may be lacerated by disease, injury, medical examination, masturbation or physical exercise. For these reasons, virginity cannot be definitively determined by examining the hymen.[22][23]
The length of the vagina varies among women of child-bearing age. Because of the presence of the cervix in the front wall of the vagina, there is a difference in length between the front wall, approximately 7.5 cm (2.5 to 3 in) long, and the back wall, approximately 9 cm (3.5 in) long.[10][24] During sexual arousal, the vagina expands both in length and width. If a woman stands upright, the vaginal canal points in an upward-backward direction and forms an angle of approximately 45 degrees with the uterus.[10